store.js

/**
 * 本地存储实现，优先本地存储localStorage，如果浏览器不支持，优雅降级为cookie
 * fork from https://github.com/marcuswestin/store.js
 */

'use strict';

// Store.js
var store = {},
	win = window,
	doc = win.document,
	localStorageName = 'localStorage',
	scriptTag = 'script',
	storage;

store.disabled = false;
store.version = '1.3.17';
store.set = function (key, value) {
};
store.get = function (key, defaultVal) {
};
store.has = function (key) {
	return store.get(key) !== undefined
};
store.remove = function (key) {
};
store.clear = function () {
};
store.transact = function (key, defaultVal, transactionFn) {
	if (transactionFn == null) {
		transactionFn = defaultVal;
		defaultVal = null;
	}
	if (defaultVal == null) {
		defaultVal = {};
	}
	var val = store.get(key, defaultVal);
	transactionFn(val);
	store.set(key, val);
};
store.getAll = function () {
};
store.forEach = function () {
};

store.serialize = function (value) {
	return JSON.stringify(value)
};
store.deserialize = function (value) {
	if (typeof value != 'string') {
		return undefined;
	}
	try {
		return JSON.parse(value);
	}
	catch (e) {
		return value || undefined;
	}
};

// Functions to encapsulate questionable FireFox 3.6.13 behavior
// when about.config::dom.storage.enabled === false
// See https://github.com/marcuswestin/store.js/issues#issue/13
function isLocalStorageNameSupported() {
	try {
		return (localStorageName in win && win[localStorageName]);
	}
	catch (err) {
		return false;
	}
}

//if support localStorage
if (isLocalStorageNameSupported()) {
	storage = win[localStorageName];
	store.set = function (key, val) {
		if (val === undefined) {
			return store.remove(key);
		}
		storage.setItem(key, store.serialize(val));
		return val;
	};
	store.get = function (key, defaultVal) {
		var val = store.deserialize(storage.getItem(key));
		return (val === undefined ? defaultVal : val);
	};
	store.remove = function (key) {
		storage.removeItem(key);
	};
	store.clear = function () {
		storage.clear();
	};
	store.getAll = function () {
		var ret = {};
		store.forEach(function (key, val) {
			ret[key] = val;
		});
		return ret;
	};
	store.forEach = function (callback) {
		for (var i = 0; i < storage.length; i++) {
			var key = storage.key(i);
			callback(key, store.get(key));
		}
	};
} else {
	var cookie = require('cookie');

	store.set = function (key, val) {
		if (val === undefined) {
			return store.remove(key);
		}
		//cookie support serialize already
		cookie.set(key, val);
		return val;
	};
	store.get = function (key, defaultVal) {
		var val = cookie.get(key);
		return (val === undefined ? defaultVal : val);
	};
	store.remove = function (key) {
		cookie.remove(key);
	};
	store.clear = function () {
		storage.clear();
	};
}

try {
	var testKey = '__storejs__';
	store.set(testKey, testKey);
	if (store.get(testKey) != testKey) {
		store.disabled = true;
	}
	store.remove(testKey);
} catch (e) {
	store.disabled = true;
}

store.enabled = !store.disabled;

module.exports = store;